Coating of piston surfaces with lead, tin, graphite or similar coatings having a predetermined thickness used to prevent the seizing of the pistons in the event of a failure in oil lubrication in the cylinders of an internal combustion engine and also in some cases to reduce engine knocking. The coating is applied in varying thicknesses and with varying coating patterns to achieve the desired results.
Hitherto the coating of engine pistons has generally been applied by spraying, which is expensive and unsatisfactory because of high losses and low efficiency. Furthermore, spraying is detrimental to the environment as large quantities of solvents are atomized.
Since the peripheral surfaces of the pistons are coated using masks when spraying, sharp contours of the piston surfaces cannot be reached. In addition, the spray mist causes undefinable coating contours under spraying masks which are not close together. Furthermore, the thickness of the coating, which is determined by adjusting the spray nozzle, normally has large tolerances.